1. Field of the Invention
This invention relates generally to radio receivers, and more particularly to methods for controlling a radio receiver receiving a hybrid signal.
2. Related Art
Many modern radio receivers for mobile reception consist of two reception paths. One reception path is used to receive, demodulate and decode a program chosen by a user while the second path is utilized to gather information from other stations. For example, the second path may be used to generate a station list or to provide traffic information.
The use of the second reception path as described is often referred to as background reception. Many modern receivers include two tuners that may be individually tuned to different frequencies. The tuners may be connected to a signal processor that is capable of demodulating and decoding both received signals individually. Many modern radio receivers include a digital signal processor that is connected to the outputs of one analog-to-digital-converter for each output signal to the two tuners. The latter receiver architecture is often referred to as a “digital IF receiver.”
To upgrade a digital IF receiver to be capable of receiving, demodulating and decoding the digital broadcast signal of a hybrid broadcast system, one of the tuners may be modified, for example, with additional filtering, and an additional signal processing path may be provided for reception of the digital broadcast signal. The additional signal processing path may be fed by the output signal of the A/D-converter connected to the modified tuner. In addition, a stage for the audio output of either the analog or the digital reception path can be chosen as output signal of the receiver (blending). In a receiver that has been modified as described, one tuner with its corresponding signal processing path is used for reception of the analog broadcast signal, and the other tuner with its corresponding signal processing path is used for reception of the digital broadcast signal of a hybrid broadcast system.
Since the modified receiver for a hybrid broadcast system includes the same hardware that is used by a normal dual receiver capable of background reception as described above, it would be desirable to use the existing receiver hardware for both purposes—reception of a hybrid broadcast signal and background reception—at the same time. This would eliminate the need for additional hardware (additional tuner and A/D-converter).
Radio receivers are often used in vehicles in combination with a navigation system guiding the user from a predetermined location to a certain destination. To calculate the fastest route to the destination, navigation systems often use information included in the received radio program containing data for traffic information that can be decoded by the receiver. The traffic information permits calculation of the fastest route to the desired destination avoiding closed or congested routes.